#include<bits/stdc++.h>
#define ll long long
#define L x<<1
#define R x<<1|1
#define mid (l+r>>1)
#define lc L,l,mid
#define rc R,mid+1,r
#define OK Ll<=l&&r<=Rr
#define Root 1,1,n
#define rep(x,y,z) for(int x=(y);x<=(z);x++)
#define per(x,y,z) for(int x=(y);x>=(z);x--)
#define repn(x) rep(x,1,n)
#define repm(x) rep(x,1,m)
#define pb push_back
#define e(x) for(int i=h[x],y=to[i];i;i=nxt[i],y=to[i])
#define E(x) for(auto y:p[x])
#define Pi pair<int,int>
#define ui unsigned ll
inline int read(){int s=0,w=1;char c=getchar();while(c<48||c>57) {if(c=='-') w=-1;c=getchar();}while(c>=48&&c<=57)s=(s<<1)+(s<<3)+c-48,c=getchar();return s*w;}
inline void pf(int x){if(x<0) putchar('-'),x=-x;if(x>9)pf(x/10);putchar(x%10+48);}
using namespace std;
const int N=1e5+10,M=2e5+5,inf=(1LL<<31)-1,mod=998244353;
const ll llf=1e18;
inline void add(int &a,int b){((a+=b)>=mod) and (a-=mod);}
inline int Add(int a,int b){return add(a,b),a;}
inline int mul(int a,int b){return 1LL*a*b%mod;}
inline void Mul(int &a,int b){a=mul(a,b);}
inline void red(int &a,int b){add(a,mod-b);}
inline int Red(int a,int b){return red(a,b),a;}
inline int qp(int a,int b){if(!b)return 1;int c=qp(a,b>>1);Mul(c,c);if(b&1)Mul(c,a);return c;}
inline int INV(int x){return qp(x,mod-2);}
int n,m,h[N],to[M],nxt[M],cnt;
inline void add_(int a,int b){
	to[++cnt]=b,nxt[cnt]=h[a],h[a]=cnt;
}
inline void clear(){
	repn(i)h[i]=0;
	cnt=0;
}
int f[N];
inline int find(int x){
	return f[x]==x?x:f[x]=find(f[x]);
}
int t[N],ans,rd[N],cd[N];
map<int,int>P[10];
bool v[N],vis[N];
inline void dfs_(int x){
	vis[x]=1;
	for(auto y:P[x])if(!vis[y.first])dfs_(y.first);
}
inline void dfs(int pos){
	if(pos==n+1){
		repn(i)f[i]=i;
		repn(i)f[find(i)]=find(t[i]),v[i]=vis[i]=rd[i]=cd[i]=0;
		repn(i)v[find(i)]=1;
		int c=0;
		repn(i)c+=v[i],P[i].clear();
		repn(x)e(x)P[find(x)][find(y)]=1;
		repn(x)for(auto y:P[x])rd[y.first]++,cd[x]++;
		repn(x)if(v[x]&&!(rd[x]==1&&cd[x]==1))return;
		repn(x)if(v[x]){
			dfs_(x);
			repn(y)if(v[y]&&!vis[y])return;
			ans=min(ans,n-c);
			return;
		}
		return;
	}
	repn(i)t[pos]=i,dfs(pos+1);
}
inline void subtask0(){
	ans=n-1,dfs(1);
	cout <<ans<<'\n';
	clear();
}
inline void Main(){
	n=read(),m=read();
	bool fl=0;
	repn(i)f[i]=i;
	repm(i){
		int x=read()+1,y=read()+1;
		add_(x,y);
		f[find(x)]=find(y);
		fl|=x==y;
	}
	if(fl)return cout <<n-1<<'\n',clear();
	if(n<=5&&m<=20)return subtask0();
	cout <<n-1<<'\n';
}
signed main(){
	freopen("circ.in","r",stdin);
	freopen("circ.out","w",stdout);
	int T=read();
	while(T--)Main();
	return 0;
}